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More than 200 of our genes may be USELESS: Genome project finds we may not need everything in our DNA to survive

Findings come from the 1000 Genome Project at University of Washington
Researchers studied the genomes of 2,500 people from across the globe
They said they were surprised to see around 1% of the 20,000 genes in the human genome were missing entirely in some participants
It suggests these genes may be redundant or not as important as thought

Published: 05:54 EST, 1 October 2015 | Updated: 21:01 EST, 1 October 2015

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By studying the genomes of people globally researchers have said humans can survive even if 200 of our 24,000 genes are missing completely

We have around 24,000 genes that make us uniquely human and, until now, it was thought that if any were missing it could cause serious problems.

But new research has found that around 200 of these genes may in fact be completely redundant, without posing any such risk.

By studying the genomes of 2,500 people, researchers have said they were surprised to see around one per cent of these genes were missing entirely in some participants.

More importantly, these particular people had no significant health defects that would be explained by the missing genes.

The findings come from the latest research carried out on the 1000 Genomes Project.

Created by researchers at the European Molecular Biology Laboratory (EMBL) and the University of Washington, the project is creating a reference catalogue of genetic variations in more than 2,500 human genomes across five continents and 18 countries.

'When we analysed the genomes, we were surprised to see over 200 genes that are missing entirely in some people,' said Jan Korbel, who led the work at EMBL in Heidelberg, Germany.

'Genome sequencing is beginning to be used for diagnostic purposes, and when doctors see that a piece of the genome is missing in a patient, there's a temptation to tie that to a diagnosis,' added Evan Eichler, who led the work at the University of Washington.

'We can now let clinicians know that there are certain genes that really should not be used to try to explain diseases in this way.'

In addition to discovering 200 potentially irrelevant genes, the latest results show how these large-scale genetic alterations vary in populations across the globe.

The latest phase of the project studied individuals from Africa, East Asia, Europe, South Asia and the Americas.

In addition to discovering potentially irrelevant genes, the latest results show how these genetic alterations vary across the globe. Dark colours are variants unique to a population, light colours are those unique to a continent, light grey are variations shared across continents and dark grey are variants seen in all continents

The researchers found 88 million variants, which mark genetic differences in populations. They found 12 million of these we seen across all continents studied, 24 million were only found in the genomes of people living in certain regions and the majority, 64 million, were 'rare', occurring in only 1% or less of the population

The researchers said the typical genome differs from a reference human genome in around 4.5 million points along the DNA strand.

In total this equates to 88 million variants, which mark genetic differences among populations.

In particular, the researchers found that 12 million of these 88 million variants we seen across all continents studied, while 24 million were only found in the genomes of people living in certain regions or populations.

Meanwhile the majority of the variants - 64 million - were considered 'rare', occurring in only one per cent or less of the population.

Genome sequencing is used for diagnostic purposes, and genetic variations can explain disorders and conditions such as colour blindness (colour blindness test pictured). The researchers said their latest research can now let clinicians know there are certain genes that can be discounted when studying disease

The group with the most variants was African, which the researchers said reflects the migration of that population to other parts of the world.

In European and Asian populations, these variations were to blame for the differences in the genome in more cases than in African populations, but African genomes have a greater diversity overall.

It is thought these variations developed in response to the participants lifestyles and in particular where they live, but further research is needed to establish more exact causes.

This research will now help guide future studies of genetics, evolution and disease and is published in Nature.

GENES PROTECT CHILDREN FROM MALARIA

In a separate paper, researchers have identified a specific genetic variation that protects some African children from developing severe malaria.

In some cases, the study found that having a specific genetic variation almost halves the child's risk of developing the disease.

The locus is near a cluster of genes which code for proteins called glycophorins involved in the parasite's invasion of red blood cells.

The results comes from analysis of data taken in Burkina Faso, Cameroon, Ghana, Kenya, Malawi, Mali, Gambia and Tanzania - comparing the DNA of children with severe malaria with the DNA of children without.

A particularly strongly-protective variant, known in genetics as an allele, was found most commonly among children in Kenya, in East Africa.

Having this allele reduces the risk of severe malaria by about 40 per cent in Kenyan children, the study found.

In a separate paper, also in Nature this week, researchers used the data from the project to identify a specific genetic variations that protects some African children from developing severe malaria.

By identifying the variations in DNA at a specific location, or locus, on the genome, the researchers were able to help explain why some children develop severe malaria and others don't, especially in communities where people are most at risk.

In some cases, the study found that having a specific genetic variation almost halves the child's risk of developing the disease.

'We can now say, unequivocally, that genetic variations in this region of the human genome provide strong protection against severe malaria in real-world settings, making a difference to whether a child lives or dies,' said lead researcher Dominic Kwiatkowski, a professor at the Wellcome Trust's Sanger Institute and Centre for Human Genetics and one of the lead researchers on the project.

The work was conducted by MalariaGEN, an international network of scientists across Africa, Asia and other malaria-endemic regions, largely funded by the Wellcome Trust.

The experts analysed data from Burkina Faso, Cameroon, Ghana, Kenya, Malawi, Mali, Gambia and Tanzania - comparing the DNA of 5,633 children with severe malaria with the DNA of 5,919 children without. They then replicated their key findings in a further 14,000 children.

The locus is near a cluster of genes which code for proteins called glycophorins involved in the malaria parasite's invasion of red blood cells.

In a separate paper, researchers have identified a specific genetic variation that protects some African children from developing severe malaria, spread by mosquitoes (stock image). In some cases, the study found that having a specific genetic variation almost halves the child's risk of developing the disease

'This new resistance locus is particularly interesting because it lies so close to genes that are gatekeepers for the malaria parasite's invasion machinery,' said Professor Kwiatkowski.

'We now need to drill down at this locus to characterise these complex patterns of genetic variation more precisely and to understand the molecular mechanisms by which they act.'

A particularly strongly-protective variant, known in genetics as an allele, was found most commonly among children in Kenya, in East Africa.

Having this allele reduces the risk of severe malaria by about 40 per cent in Kenyan children, the study found.